3. BCD-to-Excess-3 Code converter
BCD is a code for the decimal digits 0-9
Excess-3 is also a code for the decimal digits

4. Specification of BCD-to-Excess3
Inputs: a BCD input, A,B,C,D with A as the most significant bit and D as the least significant bit.
Outputs: an Excess-3 output W,X,Y,Z that corresponds to the BCD input.

5. Formulation of BCD-to-Excess-3
Excess-3 code is easily formed by adding a binary 3 to the binary or BCD for the digit.
There are 16 possible inputs for both BCD and Excess-3.